1. Field of the Invention
The present invention relates generally to improving or maximizing power output from an internal combustion engine and, more particularly, to changing engine power variables such as fuel flow, ignition timing and intake air flow, and measuring the corresponding engine power output for each power variable change until engine power output is maximized.
2. Background of the Prior Art
Internal combustion engines develop output power based upon a multiple of power variables including, but not limited to, fuel flow, ignition timing, intake air flow and many other power parameters. Prior art techniques for maximizing engine performance or “tuning” the engine, include manually adjusting an air-fuel mixture pursuant to manufacturer specifications, or using an oxygen sensor in the engine exhaust flow to provide an input to a digital computer that controls fuel flow to the engine via fuel injectors thereby forming a “closed loop” control system. The goal of the prior art control system is a stoichiometric air-fuel mixture that achieves optimum fuel economy. For gasoline, a stoichiometric air-fuel ratio that achieves optimum fuel economy is 14.7 parts air to 1 part fuel by weight. Air-fuel ratios less than 14.7 to 1 (running rich) result in decreased engine power and decreased fuel economy. Greater air-flow ratios (running lean) can damage an engine.
One prior art method (U.S. Pat. No. 6,681,752) of automatic tuning of fuel injected engines includes replacing an existing oxygen sensor with a wide band oxygen sensor in the exhaust flow to achieve a stoichiometric air-fuel ratio and optimum fuel economy.
Another prior art method (U.S. Pat. No. 6,745,620) of automatic tuning of fuel injected engines includes an oxygen sensor in the exhaust flow to provide feedback for closed loop control of an internal combustion engine's air-fuel ratio to appropriate target specifications. More specifically, the method automates the process of providing a “map” of optimum air-fuel ratios for each operating condition (a given throttle position and revolutions per minute (“RPM”)) of the vehicle.
The problem with prior art tuning methods is that internal combustion engine fuel economy is optimized instead of power output for a preselected RPM rate. Racing vehicles such as motorcycles require maximum engine power output not optimizing fuel economy. A motorcycle racing on undulating or relatively short raceways requires maximum output power at one RPM, while the same motorcycle operating on a relatively long raceway requires a maximum engine power output at a different RPM. Maximizing engine power output reduces the air-fuel ratio and fuel economy at the selected RPM rate, but increases the chance of winning the race. A tradeoff every motorcycle racer is more than willing to accept.
Besides racing vehicles, internal combustion engines are used at installations that require the engine to operate at one of two speeds, idle or at maximum RPM. These installations include, but are not limited to, pumps, compressors, and cooling fans. The maximum RPM rate for the installation, corresponds to the maximum power output required during operation of the equipment. Maximum power output is required during operation, not fuel economy.
Another problem with prior art tuning methods is that only the air-fuel ratio is controlled to achieve optimum engine performance, i.e. fuel economy. The prior art methods do not control other power variables such as engine ignition timing, intake air flow or fuel flow cooperating with carburetors to achieve optimum engine performance.
A need exist for a system and method for maximizing internal combustion engine power output for a preselected RPM by providing closed loop control that uses engine power output as a feedback signal to a digital computer, the computer providing an output signal to a controller that adjusts the magnitude of a selected power variable including, but not limited to fuel flow, ignition timing and/or intake air flow.